Acne on the left cheek can be caused by acne, folliculitis, and skin boils. 1. Acne is a chronic inflammatory disease of the skin, the causes of which are not only related to endocrine disorders, but also mental factors, environmental factors and dietary factors. The main treatment is to give anti-inflammatory and keratolytic drugs, such as fusidic acid ointment, benzoyl peroxide gel and so on. 2. Folliculitis belongs to an acute infectious disease, and its formation is not only related to skin hygiene, but also related to personal immunity and dietary factors. The treatment is mainly antibacterial, such as topical mupirocin cream, erythromycin cream. 3. Skin boils are infectious diseases that occur deep in the hair follicles. Skin hygiene and diet are factors that affect skin boils. Treatment is mainly antibacterial, such as topical levofloxacin ointment, and oral antibiotics can be combined if necessary. Due to the complexity of the etiology, a doctor’s consultation is required.